Method and apparatus for producing fixed carbureted air gas



April 11, 1933. v v w G w S 1,903,583

METHOD AND APPARATUS FOR PRODUCING FIXED CARBURETED AIR GAS Filed Dec. 8, 1950 2 Sheets-Sheet l Partial Vapor-w:

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' 'm J W M April 11, w G W T 1N METHOD AND APPARATUS FOR PRODUCING FIXED CARBURETED AIR GAS Filed Dec. 8, 1936 2 Sheets-Sheet 2 )V. G. 14% 876215 J .gwuenlot Patented Apr. 11, 1933 r UNITED STATES PATE NTL QFFI;Cal

WALTER G. wa'rxms, or ELDOBAIDO, Kansas, assrcmon r01 ELDORADO, KANSAS KELLY 012i; COMPANY, or

METHOD AND APPARATUS FOR PRODUCING FIXED CARBURETED AlIBi GAS Application filed December 8, 1930. Serial No. 500,961.

liquids and it has thereforebeen necessary with apparatus and systems heretofore known, to not only completely vaporize the liquid fuel before mixing, but to supply it to the mixers at a nearly constant temperature to reduce the variation of B. t. u. value, due to the difference in volume resulting from temperature changes. It is generally accepted by the advocates of the present plants that' the fuel consumption for vaporizing butane is 2% of the plant output, thus indicating eith' r a high loss of heat or a heating of the vapor.

Obviously, with these systems an appreciable amount of heat and extensiveequipment have been necessary to vaporize the liquid fuel, which not only added to the cost of installation, but entailed considerable expense in maintenance and operation.

One of the main objections to systems heretofore known, aside ffiim the intricacy of structure and the necessity of supplying the fuels to the mixture in the vaporous state, has been the possibility of wide variations in the B. t. u. value of the finished gas, due to the failure of the mixing devices to produce a thoroughly mixed gas.

It is the object of my invention to over.- come the objections and disadvantages heretofore encountered in systems of this character and to provide a method and apparatus wherein the liquid butane or other liquid hydrocarbon enricher is injected directly into the dilutent either as a liquid hydrocarbon or in a partially vaporized form and wherein the only energy expended is that of compressing the dilutent, which I have found in the case of a 540 B. t. u. gas is about 82% of the final gas output, when'using an enricher such as butane which has a B. t. u. value of approximately 3200 B. t. u. per cubic foot. With the proportional systems heretofore known, it has been necessary to' reduce the butane or other liquid fuel to the vapor state and to atmospheric pressure before proportioning the same and then recompress the butane vapor to line pressure which requires considerable unnecessary energy. "It will therefore be noted that there is a saving effected by my. improved method which is practically in proportion to the percentage of butane vapor mixed with the finished gas.

A further object of my invention is to provide a greater main and storage capacity, due to the increased density of the gas, caused by the cooling of the gas leaving the mixing tank by the utilization of the heat required to vaporize all or a portion of theliquid fuel I which is vaporized. In actual operation with an experimental plant, I have found it possible to maintain a temperature on the finished gas ranging from 55 to 90 F., depending on the discharge pressure of the compressor.

At three pounds, the compressor air discharge temperature was approximately 104 F., and at 14 pounds, approximately 175 F. It has been a common practice not to cool the gas from the plants and the effect of a 175 F. gas on storage capacities can be readily appreciated. Further, some-of the plantsoperate against pressures as high as 40 pounds and the results under these conditions are even more uneconomical for efiicient operation. It will thus be seen that by utilizing the heat of compression of the dilutent to vaporize aportion of the liquid fuel, which, in turn' cools the finished gas,an additional cooling system is unnecessary, and the economy and practicability of my improved system is facilitated.

It is well-known that theair or other 'fluidused for dilution is'more or lesssaturatedwith moisture at the'particular conditions under which it is taken'into the compressor, and with systems discharging 'hot finished gas, the moisture conta nedfin the'fsame results in a reductionv in the line capacity, a reduction the flame temperature of the,

gas, corrosion of the gas piping systems, and the condensation of the water in the mains under the lower pressures and temperatures ,gas, and all of the objections previously mentioned are to a great degree overcome.

A still further object of my invention is to utilize only suflicient outside heat, in addition to the heat of compression of the dilutent, to keep the system in equilibrium. This may be accomplished by the use of heated water in a jacket surrounding the partial vaporizer, to assist in supplying a portion of the latent heat of the liquid fuel, if necessary, to manufacture a finished gas of the desired B. t. u. value. acts to cool the compressor, and the compressor in turn, to warm the water for recircula-. tion in the system, thus eliminating any additional cooling system for the compressor.

The water supply used in the present systems for supplying the Vaporizers is operated at 140 to 180 F., and there is obviously a considerable heat loss when operating a system at this temperature as against operating a system at between 70 and 90 F., in accordance with my invention.

A further and very important object and advantage of my improved system is the relative ease of control, in that there is only one control, namely, a needle valve for the injection of'the liquid hydrocarbon fuel, by means of which the B. t. u. value of the finished gas is regulated. The charging of the liquid hydrocarbon fuel may be controlled by electricity or pressure, operating in unison with the compressor motor, the hand setting of the needle valve remaining constant, thus eliminating all intricate moving parts and rendering the system completely automatic.

With the above and other objects in View which will appear as the description proceeds, my invention consists in the novel features herein set forth, illustrated in the accompanymg drawings, and more particularly pointed out in the appended claims.

Referring to the drawings in which numeralsof like character designate similar parts throughout the several views,

Fig. 1 is a schematic elevation of one form of apparatus by which my improved method may be practiced.

Fig. 2 is a detail elevation of the partial vaporizer and accumulator, the former being partially broken away to illustrate the interior structure.

In the drawings, 1 represents a liquid fuel storage tank from which hydrocarbon fuel in This water further its liquid state is injected directly into the dilutent, 2 is a pressure control valve on an air line 3 in communication with the tank 1, for maintaining a constant pressure in said tank. 4 represents a fuel line which leads from the tank 1 to the inlet valve 5 of the partial vaporizer 6. 7 represents an air compressor which forces compressed and heated air through line 8 into the central conduit 9 arranged vertically within the partial vaporizer 6, see Fig. 2, said conduit being spaced apart from the walls 10 of said vaporizer to form a acket which is in communicat on with a-source of heated water 11 through the medium of a pipe line 12. In some instances the use of heated Water or other additional heat-- ing means may be eliminated.

13 represents a partial vaporizing coil connected at its upper end to the fuel line 4 by means of the needle valve 5, said valve controlling the amount of liquid fuel passing through said coil. The coil 13 is wound around the conduit 9 in the partial vaporizer 6 and its lower extremity is in communica-' tion with the interior of said conduit at a point intermediate its ends, preferably toward the lower end of the conduit as at 14.

The conduit 9 emerges at its lower end from the casing 10 of the partial vaporizer 6, and is connected by means of a pipe 15, into a mixing tank 16, which is adapted to completely mix the fuel and dilutent and to collect any moisture which may be condensed out of the air.

17 represents a conventional gas holder for storage of the finished gas and is in communication with the: mixing tank 16 through the medium of a pipe line-18.

The heated water fed into the jacket 10 through the pipe 12 is conveyed from said jacket at the upper end of the vaporizer through a pipe 19 which leads to the com pressor 7, and after circulating through said compressor, the water is conveyed by a pipe 20 back to its source 11, from whence it repeats its cycle.

Having thus described an apparatus by which my improved system of carburetion may be practiced,its operation is as follows The compressor 7 is set into operation and air is compressed under any desired pressure, but preferably between atmosphericand 100 pounds, and simultaneously the flow of liquid hydrocarbon fuel from the tank 1 into the coil 13 is started. The air is heated by its compression to the temperature cor responding to the existing pressure, and corn ducted through the pipe 8 into the conduit 9 ini'the partial vaporizing cylinder 6.

There, is carried on the storage tank 1 just sutficient pressure to create the necessary pressure differential between the storage tank pressure and the highest pressure of the discharged gas, to give a satisfactory flow of liquid n35 the"leemprg brgi seiiaige air or.

other dilutentfed from .sai'dcompressor.

For example, anexperimenta'l plant fur nished gas against discharge pressuresfrang 60 pounds pressure'on the liquid fuel storthrough the coil age tank was adequate. This air pressure was obtained from a Very small air com presser which was. also used to furnish air for unloading the liquid fuel from the tank cars into the plant storage tanks.

The liquid hydrocarbon fuel (butane for example) is conducted into said cylinder around the conduit 9 by means of the coil 13. Its flow beinggoverned by a fixed orifice of the correct size, or the needle valve 5, said valve being handset at the correct point, and with the liquid fuel pressure kept approximately constant. The butane or other liquid fuel entering the coil 13 receives a certain amount of heat from the air or dilutent-in the conduit 9, thereby expanding and'becoming partially vaporized during its travel The mixture of cold butane vapor and some unvaporized or liquid butane is then injected directly into the conduit 9 at 14:, Fig. 2, being mixed with the air stream or dilutent at this point.

The hot water from the source 11 is continuously circulated. through the jacket 10 surrounding the vaporizer and acts to further the partial vaporization of the fuel and thus provide the extra heat which may be required to keep the system in equilibrium. The water is then sent out of the'vaporizer in a cooled condition due to the loss of heat from the water in assisting in supplying a portion of the latent heat of vaporization of the butane, or other volatile liquid fuel, and is conducted through a pipe 19 to the compressor 7, where it acts to cool the compressor, and is afterwards returned to its source in a warmed condition through a pipe 20 to repeat the circulation through the system.

The mixture of air and fuel is taken from the conduit 9- in the partial vaporizer into the mixing tank 16 where as before stated, it is thoroughly mixed, and any condensate of moisture is removed. The finished cold gas is then piped to the storage tank 17 for use, its temperature having been reduced due to the cooling of the dilutent by its"supplying" all or a portion of the latent heat of vaporization to the liquid fuel. In other words, the heated air and water, or either of,these, in the partial vaporizer heats the butane, which in turn cools the dilutent and consequently the finished gas. a

In some instances it may be found that my process may be successfully carried out without the use of heated water or other liquid 'to supply any additional heat for partially vaporizing the liquid fuel, thus ing through the conduit 91 forthis purposem;

It will be noted that with this systeniyai variation in" atmospheric temperatni'eis compensated for to a marked degree," 'in that, there is a drop in atmospherictem'perature,

although-the air becomes more"de nse,'at the same t1me, the liquid butane being conducted toth'e partiali-vaporizer also becomes more the result that the additional :7

dense, with v 7 amount of butane conducted tothe' mixture; with its added B. t. u. value, compensates for the loss of B. t. u. value caused by the density of the air. 1 The foregoing contemplates themanufac-xi ture of a finished gas of approximately 540 B. t. u. and under'the prevailing conditions, the partial vaporizing'step is necessary forsatisfactory operation, It will be noted how.-

ever', that in the production of a completely premixed gas of substantially lower B. t. u.

value, for example 125 B. t. u. per cubic foot (a gas which does not require any additional oxygen for combustion) or where warmer diluent is available such as highly compressed air, my system may be carried out without the partial vaporizing step.

That is the liquid butane from the tank 1 may be injected directly into the air stream at the top of the conduit 9, in its liquid form. The reason for this is that in the manufacture of a gas of high B. t. u. value, the amount of butane requiredis such as to result in an extremely cold zone at the point of injection into the air, which would condense and freeze the moisture in the air, and on a prolonged run, would freeze the air line, while in the case of a lower B. t. u. gas, with its lesser amount of butane,this condition would not exist.

While I have mentioned butane throughout the specification as an exam 1c of a liquid hydrocarbon fuel which may e employed in my process, it is obvious that this specific I fuel is mentioned purely for the purpose of illustration and that various other hydrocarbons in liquid form may be employed with equal effect such forexample as ethane, propane, pentane and commercial butane which includes all of these substances. Furthermore, although air is set out as the preferred dilutent, it is to be understood that I may employ flue gases or other suitable base gases containing some free oxygen.

From the foregoing it will be seen that I have provided an improved method of carbureting liquefied petroleum gas and air or.

. reted air gas for heating purposes which consists in passing a heated air stream through a conduit under a pressure above atmospheric, utilizing the heat of said air by indirect contact to partially vaporize a stream of liquid butane, injecting said stream of butane directly into said air stream, partly in vaporous and partly in liquid form while the air stream is flowing, and mixing the same.

3. The method of producing fixed carbureted air gas for heating purposes which consists in compressing air and conducting it as a stream through a conduit under a pressure above atmospheric, utilizing the heat of compression of said air by indirect contact to partially vaporize a stream of liquid butane, injecting said butane stream directly into said air stream, partly in vaporous and partly in liquid form while the air stream is flowing, and mixing the same, thus chilling the finished gas.

4. The method of producing fixed carbureted air gas for heating purposes which consists in passing a stream of heated air through a conduit under a pressure above atmospheric, utilizing the heat of said air by indirect contact to partially vaporize a stream of liquid butane, injecting said stream of butane directly into said stream of air, partly in vaporous and partly in liquid form while the air stream is flowing, mixing the same,

, and controlling the B. t. u. value of the tin-- ished gas by regulating the flow of said butane into the mixture.

5. The method of producing fixed carbureted air gas for heating purposes which consists in compressing air and conducting it through a conduit under a pressure of from 1 to 100 pounds above atmospheric, utilizing the heat of compression of said air by indirect contact to partially vaporize a stream of liquid butane, injecting said butane directly into said stream of air, partly in vaporous and partly in liquid form while the air stream is flowing, mixing the same, thus chilling the finished gas, collecting the latter, and withdrawing therefrom any condensate of moisture caused by said chilling.

6. The method of producing fixed carbu with said air and stream of liquid fuel to as- .si'st in said partial vaporization, introducing said fuel directly into said air, partly in vaporous and partl in liquid form, mixing the same, and thus c illing the finished gas.

7. The method as claimed in claim 6 wherein said water, after serving to assist in the partial vaporization of the liquid fuel, is conducted, in a cooled condition, to said compressor for cooling the same, and is then recirculated through the system.

8. The method of producing fixed carbureted air gas for heating purposes which consists in flowing a confined stream of heated air under'a pressure above atmospheric, flowing a confined stream of liquid hydrocarbon fuel out of contact with but in close proximity to said first named stream, utilizing the heat of said air to partially vaporize said liquid fuel, and then introducing said fuel from the second stream, partly in vaporous and partly in liquid form, directly into the air in said first stream, and mixing the same.

9. A method as claimed in claim 8, wherein said liquid fuel is conveyed in a spiral path around said first named stream.

10. In apparatus for producing fixed carbureted air gas for heating purposes, a partial vaporizer including a conduit for heated air, a partial vaporizing coil surrounding said conduit and discharging into the'latter at a point intermediate its ends, whereby liquid hydrocarbon fuel passing through said coil is partially vaporized by the heat of the air in said conduit and then injected, partly in vaporous and partly in liquid form, directly into the air in said conduit.

11. Apparatus for producing fixed carbureted air gas for heating purposes, including a source of liquid hydrocarbon fuel supply, an air compressor, means for utilizing the heat of compression of the air fed from said compressor, for partially vaporizing said liquid fuel, means for mixing said fuel, partly in vaporous and partly in liquid form, directly withsaid air, and a water jacket surrounding said partial vaporizing means and adapted to contain heated water for assisting in said partial vaporization.

12. Apparatus as claimed in claim 11, wherein means are provided for conducting said water, after having cooled in passing through said partial vaporizing means, to said compressor for cooling the latter and thereafter recirculating said water.

13. Apparatus for producing fixed carbu reted air gas for heating purposes including a source of liquid hydrocarbon fuel supply,

a partial vaporizer comprising a central conduit, a coil surrounding said conduit and in communication with the latter at a point intermediate its ends, and a water jacket surrounding said conduit and coil, an air compressor for forcing compressed air through said conduit in the partial vaporizer, means for conducting liquid fuel from said source r of supply into said coil, a control valve for 1 regulating the flow of said fuel through said coil, means for supplying heated water to said water jacket, means for conductin said water from said jacket in a cooled con ition,

to said compressor for cooling the latter, and

means for recirculating said water through said system.

14. The method of producing a fixed carbureted gas for heating purposes which consists in passing a suitable heated dilutent 2 through a conduit under a pressure above atmospheric, utilizing the heat of said dilutent by indirect contact to partially vaporize a stream of liquidhydrocarbon fuel, injecting said stream of hydrocarbon fuel directly into said stream of dilutent, partly in vaporous and partly in liquid form, and mixing the same.

In testimony whereof I aflix my signature.

WALTER G. WATKINS. 

